Many different kinds of packaged products, such as food, beverages and pharmaceuticals, can be adversely impacted through exposure to oxygen. The presence of oxygen in a package can cause oxygen contamination of the product being stored therein. The reaction of oxygen with chemicals present in foods and beverages can impact their odor and flavor. The reaction of oxygen with pharmaceuticals can impact their efficacy.
Molecular oxygen (O2) can react with a number of different compounds that are found in a number of foods and beverages. Molecular oxygen can be reduced by other molecules through the addition of electrons to form, e.g., a superoxide, a hydroxyl radical, or hydrogen peroxide. Each of these reduced forms of oxygen is very reactive and is thus likely to react with a number of products in the food and beverage industry. The reduced forms of oxygen are especially likely to react with the carbon-carbon double bonds found in almost all products with complex organic components. This reaction can cause the rapid degradation of the product. For example, the oxidated product may have an altered odor or flavor.
During storage of containers, particularly after any initial seal has been ruptured by a first opening of a container, often air, including oxygen, can leak and migrate into an ostensibly closed container through gaps between the container and the closure. This influx of oxygen and other airborne contaminants can be detrimental to the materials stored in the container. For this and other reasons, it is preferable to have a container and closure combination that forms a good seal.